Suction type carburetor



June 12, 1956 BURROWS ETAL 2,750,172

SUCTION TYPE CARBURETOR 2 Sheets-Sheet 1 Filed Oct. 30, 1951 In wen 07'sJfi/fard .U. Burrows QSLQWZeg Z. 523067? jfarzy fiaider g' p m WAJzzorzzeys June 12, 1956 M, D, BURROWS ET AL 2,750,172

SUCTION TYPE CARBURETOR IIIIII41 SUCTION TYPE CARBURETOR Milford D.Burrows, Stanley Z. Siwek, and Harry Goldberg, Chicago, Ill., assignorsto Pioneer Gen-E-Motor Corporation, Chicago, Ill., a corporation ofDelaware Application October 30, 1951, Serial No. 253,876

4 Claims. (Cl. 261-72) This invention relates to an improvement insuction type carburetors.

The invention has as one object to effect a mixing of fuel prior to theentry of the fuel into the induction passage.

Another object is to bring about an increase in power produced per unitof fuel used.

Another object is to increase the efliciency of the carburetor at theextremes of fuel level, and to stabilize the fuel-air ratio through therange of fuel levels.

Another object is to bring about a smoother transition than haspreviously existed in the change from the flow of fuel for idling to theflow of fuel for power.

Another object is to cool the carburetor by causing the incoming air topass through an extensive metal passage before entering the injectionchamber and thus to absorb heat from the carburetor.

Other objects will appear from time to time throughout the specificationand claims.

The invention is illustrated more or less diagrammatically in theaccompanying drawings, wherein:

Figure 1 is a plan view of a carburetor embodying my invention inposition upon a fuel tank, the path of the air therethrough being shownby arrows and with some parts shown in dotted lines.

Figure 2 is a side elevation of my invention similarly mounted and withparts broken away.

Figure 3 is a horizontal longitudinal section taken along line 3--3 ofFigure 2.

Figure 4 is a side elevation showing in detail that side of thecarburetor on which the flow of fuel and air is regulated.

Figure 5 is an enlarged section taken along line 55 of Figure 4.

Figure 6 is a sectional detail taken along line 66 of Figure 5.

Figure 7 is a section taken along line 77 of Figure 4, showing thebutterfly valve in the full open position.

Figure 8 is a variant form shown in section showing the valve in theidling position.

Figure 9 is a section taken on line 9-9 of Figure 8.

1 indicates generally a suction type carburetor, shown in Figures 1 and2 as being mounted in operative position upon a fuel tank 2. Thecarburetor 1 may be secured to the fuel tank 2 by means of a flange 3, aboss 4, and bolts 5 passing through said flange and said boss intobolt-receiving openings in the upper surface of the fuel tank 2 as at 7.

As shown in Figures 1 and 2, the flange 3 also extends beyond the uppersurface of fuel tank 2 so that bolts 8 may pass through the flange as at9 and secure to the body at that point a downwardly extending intakemanifold 10, preferably provided with a filter 10a. The intake manifold10, which could also be integral with the carburetor body if that formwere desired, preferably and for reasons appearing later in thespecification, joins the underside of the body at the remote or closedend 11 of an air passage 12. The air passage12 extends,-as shown nitedStates Patent 0 2,750,172 Patented June 12, 1956 most clearly in Figures1 and 3, to an area designated generally as 13 which is adjacent themouth 14 of an having at its lower end a projection 22 and slightlyabove its lower end a transverse slot 23. The projection 22 pivots in ahole 24 and is secured by a bolt. 25 which is in threaded engagementwith a hole slightly above the hole 24. A washer 26 rests against thatpart of the lever 21 which defines the slot 23, and a spring 27 extendsbetween the head of the bolt 25 and the washer 26. The tightness of thelever 21 against the side of the carburetor may thus be adjusted, andthe lever 21 may be moved to and held at any position along the travelof bolt 25 in the slot 23. A wire 29 may be used to connect an extension30 on the upper surface 28 of the valve 19 to the governor vane of theengine (not shown). A governor spring 29a may be used extending from asuitable securing point 29b on the wire 29 to the lever 21, for thepurpose of securing the desired adjustment against accidental changesdue to vibrations, etc. To provide stops for the control of valverotation, any stationary or fixed member such as abutment 31 on thecarburetor body 1 for use in conjunction with a stop 32 and theextension 30 on the valve surface, is satisfactory. A screw 33 threadedinto the extension 30, as shown in Figures 1 and 4, may be used toadjust the idling position of the valve 19 by determining the point towhich the abutment 31 will cause the extension 30 to be interrupted inits rotation. Vertical displacement of the valve is prevented by aretaining member 34, having a portion 35 which overlies the valvesurface 28 and which is removably secured to the carburetor by the bolt5 which passes through the boss 4 and is one of the bolts securing thecarburetor to the fuel tank.

Fuel is introduced into the carburetor by means of fuel pipe 36 whichextends downwardly into fuel tank 2 and which preferably has at itslower end a strainer element 37 and ball-check 38. As best illustratedin Figures 5 and 8, the fuel pipe introduces fuel into a fuel-receivingchamber 39, whence the fuel passes through a restricted opening 40 inseparating member 41 into a fueland airmixing chamber 42. This form is aconvenient form, since a plug 48 is easily applied and may be removedfor inspection. An alternative would be simply to have the fuel pipe 36lead directly to the member, such as 41, which contains the opening 40that leads into the mixing chamber 42. This latter, or mixing chamber,communicates with the valve 19 and the induction passage 15 by anorifice 43 or preferably by orifices 43 and 44, the smaller orifice 43being for the admission of fuel into the induction chamber for idling,the larger orifice 44 for power.

In order to effect the introduction of air into the mixing chamber 42,we provide a bleed from air passage 12. Such a bleed is mostconveniently provided by running a channel 45 along the flat inner orbottom surface of the carburetor bodysuch surface being generallydesignated as 46 and being on a plane with the under surface of theflange 3-from air passage 12 to a point from which a small air bleedhole 47 may easily be extended into the mixing chamber 42. This channel45 is shown in dotted lines in the horizontal longitudinal section ofFigure 3 and is shown in section in Figure 6. The location of the originof the bleed hole 47 is shown in Figure 3; its course from channel 45 isshown in dotted lines in Figure 4; it is shown in section in Figure 6;and its point of entry into mixing chamber 42 is indicated in Figuresand 6. Any suitable means, such as a removable plug 48 in threadedengagement with the inner walls of the housing portion 49, may be usedto seal the fuel-receiving chamber 39.

, The carburetor assembly is secured to an engine cylinder 50 by meansof a flange 51 provided at the outlet end of induction passage 15 'andthrough holes 52 through which bolts 53 may 'pass to engage the enginecylinder.

In the operation of the carburetor, fuel from the tank 2 is drawnupwardly through the fuel pipe 36, while air is sucked upwardly into theintake manifold 10. As stated previously, the air is preferablyintroduced by intake manifold 10 to the air passage 12 at the remote orclosed end 11 thereof. Introduction of the air at this pointaccomplishes two desirable purposes. It provides for a long travel ofair within the carburetor prior to the airs mixture with the fuel. Thistravel of the air through air passage 12 provides for cooling of thecarburetor since the air in its course through the passage 12 willabsorb heat given off to the carburetor from the engine. Secondly, theintroduction of intake air at this point renders easy and convenient thebleeding off of a part thereof into channel 45 and air bleed hole 47 aspreviously discussed. It is, ofcourse, true that the air bleed couldenter the mixing chamber 42 directly-from the atmosphere, or from anyoutside source, as through an orifice 47 (a) such as that shown inFigures 8 and 9. The only real disadvantage to introducing air by anorifice such as the direct atmosphere-to-mixing-chamber orifice 47(w) isthat such air is unfiltered, or at least is not as conveniently filteredas is air taken in originally through a filtered intake, as 10 and10(a). There is, however, no reason why, aside from impurities in theair, a direct orifice such as 47 (a) cannot be just as efiicient forfuel-air mixing purposes as can an air bleed taken'olf the main airpassage 12.

Let it be assumed that the choke 16 is at least partially open. In thatcase the intake air, minus the small portion thereof which is bled offinto the mixing chamber in the manner hereinbefore set forth, turns atportion 13 and enters induction passage 15. Let it also be assumed thatthe valve 19 is full open, or at least open past the power orifice 44 ifboth a power and a separate idling orifice are used. In such a case theair continues through the induction passage and on into the enginecylinder. While passing through the valve the air creates the suctionwhich causes the fuel to be drawn through the orifice or orificescommunicating between mixing chamber 42 and the induction passage 15.What we shall refer to as the bled air, which enters the mixing chamber42 through a restricted opening, causes mixing of air and gas in themixing chamber. As each droplet of fuel passes through the orifice 40and into the mixing chamber 42, it is caught in turbulent air. The sizeof the units of fuel introduced through the orifice 40 is immediatelyreduced by this turbulence, and as the fuel continues to be introducedinto this turbulent air within the mixing chamber, a vapor is formedwith the result that no raw fuel, completely unmixed with air, dripsinto the valve 19 through orifice 43 or 44.

Experience has shown that even in the absence of a mixing chamber suchas is disclosed herein, some air space must be provided between theoutlet orifice in what we have termed fuel-receiving chamber 39 and theorifice or orifices leading into the induction chamber. Otherwise thereis too much surface tension to allow for an even How of fuel into theinduction chamber. In all cases in which some air space at this point ispresent, if a needle valve or metering pin is used, some raw fuel willdrip into such chamber or air space about the needle or pin and will inturn be drawn outinto the induction passage in excessively large drops.Similarly, when no such valve means of adjusting fuel flow into thepreinduction air space is used, raw fuel is sucked through an orificesuch as 40 and passes through and out of the non-turbulent air spaceunmixed. This difficulty and the attendant engine inefficiency are to avery great degree eliminated by the air bleed structure disclosedherein, which results in the formation of a passage of air which isconstantly and rapidly moving through the mixing chamber and whichenters that chamber from an angle different from the angle of entry ofthe fuel, and which thereby collides with the fuel and causes the fuelparticles to be broken up while they are still within and passingthrough the mixing chamber.

The provision of the mixing chamber described herein has, in tests,demonstrated specific improvements in engine performance. When a suctiontype carburetor without an air bleed is adjusted for good performanceand power output at a relatively high engine speed, then at lower enginespeeds at no-load conditions, the fuel-air ratio is too rich forsatisfactory performance. When the engine is adjusted for good idling,then at the higher engine speeds, the fuel-air ratio is too lean forsatisfactory performance. The bleed hole leading into a fuel-air-mixingchamber between the fuel-receiving chamber and the orifices whichdischarge into the induction passage of the carburetor affects the flowof gasoline into the mixing chamber by converting the liquid gasoline toan atomized mixture. When the carburetor is adjusted for goodperformance at the higher engine speed the gasoline is mixed with air inthe mixing chamber before being discharged through the orifices into thebutterfly valve, The mixture of air and gasoline into the carburetorthroat is thus atomized and made more homogeneous; and more economicaland efiicient engine performance is achieved than is otherwise possibleto effect.

Furthermore, in this type of carburetor, wherein fuel must be liftedbefore it can be used, the efliciency of the engine decreases as thefuel level lowers. This is true because as the fuel level lowers itbecomes increasingly difficult to raise the smaller amount of fuel whichis near the bottom of the fuel tank. Our invention does not increase thesuction available and, therefore, does not cause any increased lifting,but it does cause a much better mixture of fuel and air than is possiblewithout the air bleed, and thus each unit of fuel produces more powerthan it otherwise would. As a result, the loss of power which isnoticeable when the fuel level is low in any suction type carburetorwithout our invention is to a great degree eliminated in the structurewhich we disclose and claim, wherein each particle of lifted fuel isbroken up and mixed with air before it enters the induction passage.

Although we have shown an operative form of our invention, it will berecognized that many changes in the form, shape and arrangement of partscan be made without departing from the spirit of the invention, and ourshowing is, therefore, to be taken as, in a sense, diagrammatic.

We claim:

1. A fioatless suction type carburetor assembly wherein the fuel tank isbelow the induction passage, the induction passage being open at one endfor communication with the intake port of an engine cylinder, and havingan air inlet in communication with the outside air supply, saidcarburetor assembly including a housing portion defining a fuel and airmixing chamber adjacent said induction passage, a jet orifice openingfrom said fuel and air mixing chamber into said induction passage at azone of reduced pressure, means for delivering fuel to said fuel and airmixing chamber including a depending fuel carrying conduit communicatingthrough a restricted orifice with said fuel and air mixing chamber andextending downwardly into said fuel tank, and an air bleed passageextending from the outside air supply and through said housing portionand into said fuel and air mixing chamber, said air bleed passage beingangularly arranged with respect to the axis of said restricted orificeto supply a stream of air to said chamber in a direction other thansubstantially parallel to the direction of entry of the fuel into saidchamber.

2. A floatless suction type carburetor assembly wherein the fuel tank isbelow the induction passage, the in duction passage being open at oneend for communication with the intake port of an engine cylinder, andhaving an air inlet in communication with the outside air supply, saidassembly including a housing having a bore therein, said bore extendingtransversely to said induction passage and communicating through a jetorifice with said induction passage at a zone of reduced pressure, meansdividing said bore into a fuel receiving chamber and a fuel and airmixing chamber, a restricted orifice allowing communication between saidchambers, means for supplying fuel to said fuel receiving chambercomprising a depending fuel carrying conduit in communication with saidfuel receiving chamber and extending downwardly into said fuel tank,said induction passage having contiguous portions providing a change inthe direction of the flow of air through said induction passage from thepoint of connection with said air inlet, and an air bleed passageextending from said air inlet passage to said fuel and air mixingchamber, said air bleed passage being angularly arranged with respect tothe axis of said restricted orifice.

3. The structure of claim 2 wherein said air bleed passage enters saidfuel and air mixing chamber along an axis extending approximately atright angles to the direction of entry of fuel to said fuel and airmixing chamber.

4. The structure of claim 2 characterized by and including a housingportion having an internally threaded bore and an inner and an outermember spaced apart from each other and in threaded engagement with saidbore, the inner member defining said fuel and air mixing chamber withthe inner end of the bore, said inner member defining said fuelreceiving chamber with said outer member and said bore.

References Cited in the file of this patent UNITED STATES PATENTS1,707,229 Lloyd Apr. 2, 1929 2,024,419 Ball et al. Dec. 17, 19352,093,011 Grosz Sept. 14, 1937 2,127,444 Emerson Aug. 16, 1938 2,157,074Ericson May 2, 1939 2,407,535 Carlson et al. Sept. 10, 1946 2,529,242Brown et al. Nov. 7, 1950 2,590,217 Snyder et al. Mar. 25, 19522,618,474 Agar Nov. 18, 1952 2,627,852 Dittmer Feb. 10, 1953 2,635,861Olson Apr. 21, 1953

